WASHINGTON — President Trump has picked Joseph J. Simons, a veteran antitrust lawyer who has represented tech giants like Microsoft, to lead the Federal Trade Commission at a time of broad bipartisan concern over corporate consolidation and big deals in the waiting, the White House said Thursday.

Mr. Trump has also chosen Noah Phillips, chief counsel for Senator John Cornyn, Republican of Texas, and Rohit Chopra, a fellow at a consumer advocacy group, to fill the remaining two seats at the agency, said Natalie M. Strom, assistant press secretary at the White House.

The consumer protection and competition agency has been led by just two commissioners over the last 10 months. Mr. Trump’s other leading antitrust official, Makan Delrahim, was recently confirmed to lead competition cases at the Justice Department.

The timing of the official nominations is unclear. They will be reviewed by Congress but are expected to be approved.

Under Mr. Simons, who led the competition bureau of the Federal Trade Commission during the George W. Bush administration, the agency is expected take a free-markets and conservative approach to antitrust issues, maintaining decades-long interpretations of competition laws that put consumer welfare and the efficiencies of markets at the center of enforcement actions and merger reviews.

But the traditional antitrust perspective could be tested by new skepticism over the power of big internet companies such as Google, Facebook and Amazon. Politicians from both parties, and many consumer interest advocates and academics, have called for greater restraints on tech companies that have quickly expanded their dominance in digital advertising, commerce and public opinion, as seen with the role social media firms like Facebook and Twitter played in the 2016 presidential election.

Throughout the Obama administration, the agency was viewed as taking a light touch with the tech sector, particularly with its decision to close an antitrust investigation into Google’s search practices in 2013. European regulators, meanwhile, took action against Google on antitrust and have pushed for new regulations over the internet sector.

Amazon’s $4.3 billion purchase of Whole Foods was quickly approved by the F.T.C. in August, largely because of ample competition in the grocery foods market.

But some antitrust academics and politicians criticized the fast review, saying the government needed to look more broadly at whether Amazon’s ability to take losses and leverage other parts of its businesses harmed competition.

Senator Richard Blumenthal, Democrat from Connecticut, has called on the agency to reopen an antitrust investigation into Google that was closed in 2013, saying new evidence from a parallel investigation in Europe warrants a new look. Stephen K. Bannon, the former senior adviser to Mr. Trump, has called Google a utility-like monopoly that needs antitrust scrutiny.

Mr. Simons comes from the Washington offices of the law firm Paul Weiss, where he served as a partner representing big tech clients including Microsoft and Sony in a $4 billion acquisition of patents from Nortel Networks. He also represented Mastercard in antitrust class-action cases against the credit card company in federal court. But like many of Mr. Trump’s picks for corporate watchdog roles, Mr. Simons has been in and out of the private and public sector for years.

Since the election, moderate Democrats and Republicans have trained their focus on corporate consolidation. The new climate, antitrust experts say, makes it difficult to predict how Mr. Simons will act.

“We’ve been waiting so long for leadership at the agencies, we are out of the speculation business until we see some enforcement under the new antitrust chiefs,” said Diana Moss, president of the American Antitrust Institute.

Jeffrey Chester, head of the nonprofit Center for Digital Democracy, a group that has pushed for online privacy regulations and stronger competition enforcement, said the agency was “at a critical turning point about whether it can be relevant at all protecting consumers in the 21st century.”

“It has been unable to effectively address the dramatic loss of privacy Americans face online,” he added. “The commission has also failed to effectively tackle the growing power of the major internet companies, especially Google and Facebook.”

A version of this article appears in print on , on Page B3 of the New York edition with the headline: Amid Concerns Over Consolidation, Trump Picks Antitrust Lawyer to Lead F.T.C.. Order Reprints | Today’s Paper | Subscribe